Delayed action cam mechanism



Sept. 29, 2- M. F. WEAVER 2,297,090

DELAYED ACTION CAM MECHANISM Filed Jan. 14, 1942 2 Sheets-Sheet 1 rINVENTOR W1 JFFTJ. v

Sept. 29, 1942. M. F. WEAVER DELAYED ACTION CAM MECHANISM 2 sheets-Sheet2 Filed Jan. 14, 1942 INVENTOR Patented Sept. 29. 1942 MUN-[TED STATESATENT OFFICE 1 Monte F. Weaver, Monroe, Mich. Application January 14,1942 Serial No. 426,697

8 Claims.

This invention relates to cam mechanisms,

more particularly it relates to a delayed action nism actuated by anintermittent operating shaft for operating an air valve to provide airfor ejecting or blowing stamped pieces out of the die or blowing it asit drops from the die so that it will not fall on the lower die or onthe new blank and ruin the parts or even the dies when the next punchingor pressing operation takes place. This'also eliminates the need of theoperator to remove the part from the upper die if it sticks there or toremove it if it falls on the lower die. It can also be used to blowchips and the likefrom piecesformed in a punch press or similar pressingmachine.

Punch presses are usually provided with a cam for operating an airvalve. The air valve allows air. from a compressed source of supply, topass through a passageway and then is directed at the formed piece or atthe dies to remove the stamped piece, chips, dirt, or any other foreignmaterial. These cams are located on an intermittently operating shaft.Since all parts of a punch press intermittently, the-cam can only beplaced on a shaft that is in motion during the-punching or pressingoperation. The best-time to eject the pressed part is whilethe press iscoming to rest and for a short period thereafter. During this time thepunched or pressed piece tends to fall from the die or can be blown.from the die and blown to a point where it does not interfere with thefollowing cycle of operation. At this time it also permits the air toblow the chips and dirt from either or both the part and the dies. Thepresent type of cam arran'gement does not provide any blowing actionafter the machine comes to rest after the punching or pressing operationbecause the cam must provide for the closing of the air valve while itis still in motion. Therefore, the present type of cam does not provide'an air stream for ejecting the part cleaning the dies at the mostessential time. 7

My invention provides a novel cam mechanism adapted to keep the airvalve open a predetermined length of'time after the operating shaftcomes to rest or stops. then closed to prevent the use of excessivequantities of compressed. air. My novel invention provides a primary,or, positive action cam plate.

The air valve is a secondary or delayed action cam plate operated bymeans of spring action after the valve is opened andthe shaft and maincam stop or come to rest, thus keeping the valve open a predeterminedlength of time after the machine stops.

My invention has for its principal obJect the provision of a delayed camaction for operating an air valve to provide an air blast for ejectingor ,removing the pressed part from the die in order to increase thecapacity-of the machine and at the same time eliminate the possibilityof the dies being ruined.

Another object of my invention is to provide an air blast at a timeadvantageous to remove chips and dirt from the die. v

My invention will be best understood from the detailed description andclaims which follow, reference being had to the accompanying drawings inwhich a preferred embodiment of the invention is shown by way of exampleand in which: l l

Fig. 1 is a; front elevation showing my novel valve mechanism.

Fig. 2 is a sectional view taken along line 22 of Fig. 1 looking. in thedirection indicated by the arrows.

Fig. 3 is a pictorial view of the main or positive action cam plate.

30 Fig. 4 is a pictorial view of the delayed'action cam plate.

- Fig. 5 is a pictorial view of the hub upon which the delayed actioncam plateoperates.

Fig. 6 is a pictorial view of the stop pin used 35 to limit theindependent motion of the delayed action cam plate.

' Fig. 7 is a pictorial view of the spring tension adjusting ring.

Fig. 8 is a front elevation of my cam arrangement together with adiagrammatic representation of the air valve that it operates.

delayed cam action mechanism in one of its operative positions.

Fig. 10 is a front elevation of my delayed cam action mechanismshowingthe cam. follower in a position where the air valve is open.

Fig. 11 is a front elevation showing the delayed action cam holding thevalve open after the action of the machine has ceased.

Fig. 12 is a front elevation showing'the position my delayed 'cam actionmechanism come to rest after its cycle of operation. r

Fig. 13 shows a fragmentary view of a modifastened to a shaft foropening the air valve and fled form of the positive action cam plate.

' anchor pin 2|.

hole I8 of the positive action cam II.

7 Referring to the drawings Ills punch press or. other pressingmachineshaft, that operates intermittently. mechanism isfastened to the end ofthe shaft My novel delayed valve action Ilf The mechanism comprises apositive action :camJI shown in Fig.3. The positive action cam II isProvided with holes I! used'to secure the cam rigidly to the shaft IIIwhen assembled. The positive action cam is further providedwith anaperture I9 adapted to hold. the stop pin I9. The delayed action cam I2shown in Fig. 4 is provided with an aperture l4 for operating on theouter surface I5 of the hub I3. The delayed action cam is furtherprovided with an elongated curved slot I5 and a hole '29 to hold thespring Fig. 5 shows the hub I3 with the larger bearing surface I5 andthe smaller surface 22. The hub I3 also has two annular holes 23 used tosecure the hub in position. Fig. 6 shows the stop pin I9 which isfastened in th; Fig. discloses the spring tension adiusting ring 23which is provided with atapped hole 24 adapted to receive a screw forsecuring the end of the spring 25.

the bearing surface I5 of the hub I3 operates in the aperture I4. Thestop pin I9, fastened in the aperture |8 of the positive action cam II,operates in the elongated slot I 6. The spring tension adjusting ring 23is then placed on the' smaller'bearing surface 22 of the hub I3. Capscrews 21 provided with washers 28 are inserted through the holes 23 ofthe hub and I I of the positive action cam. and are then'screwed intotapped holes 26 in the end of the shaft I0 holding the entire unitassembled and securing the unit to the shaft.

I The position of the cam II is fixed when the unit is assembled. Thehub I3 is also rigidly se cured and is pressed against the positiveaction camplate II. The cam plate I2 is slightly thinner than. the widthof the bearing surface I5 of the hub I3, thus providing sufficientclearance to permit free rotary movement of the cam plate I2 on thehubI3. The spring tension adjusting ring 23 holds the delayed action camplate I2 on thehub I3. The spring tension adjusting ring 23 is fastenedin a predetermined position on the hub I3 when the cap screws 21 aretightened. One end of the tension spring 25 is secured to the springanchor pin 2I,- While the other end of the spring is secured to thespring tension adjusting ring 23 by means of a screw 49 which isfastened in the tapped hole 24.

The roller cam follower 29 is held against the outer surface of the camplates II and I2 by means of spring pressure or other suitable pressure.The cam follower and the link 30 are limited to radial motion only. Whenthe cam follower 29 is in its lower position the air valve operatedby'the link 30 is closed. As soon as the cam raises the follower 29, theair valve opens and it remains open until the cam allows the roller 29to return to the lower position. In order to keep the valve open afterthe motion of the shaft I0 stops the cam must provide 'motion after theshaftstops. This is accomplished by the use of thedelayed action'cam I2and the spring 25.

.The delayed action cam plate I2- is not rigidly secured'to the rest ofthe unit,.insteadit is permitted to oscillate on thehub I 3. The extentof oscillation is limited by the length rof the slot li.

Thetension of the spring- 25 tends to ,hold the delayed action cam plateI2 in a position relative to the positive action cam plate II as shownin Fig. 1. I l

The positive action cam shown in Fig. 3 is pro-- vided with a rapidrising lobe 3|, which immediately falls'rapidly. The remainder of thecam plate II is circular. The delayed actic cam plate I2 shown in Fig. 4is provided with a circular portion of the same'radius as the circularportion of the camplate Ii, for aboutthreefourths of its circumference.The remainder of the circumference is'provided with a substantiallyinstantaneous rise shown at32. The radius remains constant after thispoint of instantaneous rise for a substantial period as shown at 33 andthen drops back to the original radius.

In operation the'shaft III operates-intermittently, one revolution beingone cycle of operation. As the shaft III begins a new revolution theentire valve assembly rotates with the shaft III as aunit in directionindicated by the arrow in Fig. 1. During this time the cam follower 29rolls on both cam faces as shown in Fig. 2. The valve 34 being in aclosed position while the cam follower 29 is on the lower cam surfaces,such as shown in I, 2 and 8. As the entire unit continues to rotate, theradial face 32 of the delayed action cam I2 contacts the roller follower29 as shown in Fig. 8. The delayed action cam I2 stops in this positionwhile the remainder of the unit continues to turn. One end of the spring25 is fastened to the stop pin 2| and-the othe end is fastened to thespring tension adjusting ring by means of the screw 40. When the delayedaction cam plate I2 stops and the remainder of the unit continues torotate, the spring 25 is expanded thus storing up energy in the spring25. Fig. 9 shows my delayed cam vactionmechanism in a position where thespring 25 has been partially expanded. The delayed action cam I2 isstill prevented from turning by the cam follower 29 while the lobe, 3|of the positive action cam plate II has contacted the roller follower29. As the positive action cam plate II. continues to rotate, thefollower 29 is moved up or outward radially from the center of the camand shaft. This radial movement of the cam roller follower 29 opens thevalve 34 by means of a link member 30. As the unit'continues to turn thecam lobe 3| lifts the cam follower 29 to its maximum height as shown inFig. 10. In this position the spring 25 has been fully expanded and thedelayed action cam has been released because the cam roller follower 29has been lifted, by the lobe 3| of the positive action cam plate II,unto the top surface of the cam lobe 33. From the position shown in Fig.10 the entire unit continues to rotate until the shaft I 0'stops at theend of its cycle. The plate II being rigidly secured to the shaft IIIalso stops when the shaft stops the lobe 3|, then being in the positionshown in Fig. 11. The camfollower 29 rides on the upper surface of thecam lobe 33' after remainafter the remainder of the unit'and. the shaftIII stop. Thus, the valve 34 is held open after all other'motion of thecycle of operation ceases.

Fig. 11 shows the positive action cam II in its stopping position whilethe delayed action cam continues to turn on the hub l3 due to thetension of the spring 35. The valve 34 is held open until the rollerfollower 29 drops from the cam lobe 33 back to the lower circularportion of the delayed action cam plate. Thedelayed action cam platecomes to rest when the stop pin I3 engages with the end of the elongatedslot l6 as shown in Fig. 12. Fig. 12 shows the delayed radial motion.The bracket 35 is fastened to the punch press or machine indicated at36. An inlet line 31 carries compressed air from a source of supply tothe valve 34 while the line 38 carries the compressed air from the valve.34 to, the point where it is used to eject the stamped part or to blowchips and dirt from the dies orthestamped piece.

From the above description it will be noted that my novel device keepsthe air valve 34 open for an. appreciable'lengthof time after the punchpress or pressing machine stops. As stated previously, the desirabletime for providing the air blast for cleaning is immediately after thepress stops. As the press stops the stamped piece tends to fall from thedie and this is the proper time for the air blast to. occur. In thepresent valve arrangement for presses, a cam is fastened on the pressshaft. This cam must necessarily open and close the valve while themachine is still in motion. Thus the air blast is provided before themachine stops at the end of its. cycle which is too early. My improvedcam mechanism provides motion or cam action after the press stops. Mydevice does not close the air valve until after the press or machinestops which provides an air blast at the desirable time. The period ofvalve opening can be varied by changing the length of the cam lobe 33.The period can also be governed by changing the tension in the spring25. This is accomplished by turning the spring tension adjusting ring23, After the desired tension is obtained in the spring 25, the springtension adjusting ring is held in position by the cap screws 21.

The positive action cam plate II can be provided with a notched openingat its center as shown in Fig. 13 in place of the holes H. The notches33 engage with the cap screw 21 looking the cam in position. The notches39 provide a means for changing the position of the positive action camplate H with respect to the shaft Ill. The change of position provides ameans for varying the time at which the valve opens.

My novel delayed action cam mechanism provides' a very. fiexiblearrangement for opening and closing the air valve 34. The opening of thevalve can be made to occur sooner or later in the cycle by changing theposition of the fixed cam II with respect to the shaft Ill. The closingof the valve canbe made to occur earlier or later in the cycle bydecreasing or increasing theJength of the delayed action cam lobe 33.The time of closing can be further modified by altering the tension inthe coil spring 23.

be used to operate mechanisms other than air valves.

While I have described the details of one form I of my invention, I donot wish to be limited to the particular form shown and described as itwill be apparent many modifications therein may be made withoutdeparting from the scope of my invention.

Having thus described my invention, what I claim is:

1. A cam mechanism comprising; a fixed cam plate rigidly mounted on ashaft, a hub'secured to said shaft, an auxiliary cam plate mounted onsaid hub and adapted to oscillate thereon, a means for limiting theoscillation of said auxiliary cam plate, in respect to said fixed camplate, a spring tending to hold said fixed cam plate and said auxiliarycam plate in a predetermined position with respect to each other, a camfollower in operative engagement with said fixed cam plate and saidauxiliary cam plate; said fixed cam plate adapted to move said cam fol-'lower outward radially and said auxiliary cam plate adapted to hold saidcam follower in said outward position for a predetermined period afterthe motion of said. fixed cam plate ceases.

2; A cam mechanism comprising; a fixed primary cam platesecurely mountedon a shaft, a

hub secured to said shaft; an auxiliary cam plate mounted on said huband adapted to oscillate in axial alignment with respect to said primary3. A- cam mechanism comprising; a hub, said hub being rigidly secured toa shaft; a primary cam plate interposed between said hub and said shaft;a secondary cam plate mounted on said hub and adapted to oscillate withrespect to said primary cam plate, said secondary cam plate having anelongated slot, said primary cam plate being provided with a stop pinarranged to travel in said elongated slot and restrict the travel ofsaid secondary cam plate; a spring tending-to hold one end of said slotagainst said stop pin; a' ring adapted to retain said secondary camplate on said hub, said ring also adapted to adjust the tension in saidspring; and a cam follower; said secondary cam plate being provided witha substantial instantaneous rise for contacting said ramfcllower; saidprimary cam plate being provided with a lobe for moving saidcam'follower radially outwardly, whereby-secondary cam plate is releasedand allowed to advance holding said cam follower in said outwardposition for a predetermined length of time after the rotary movement ofsaid primary cam plate ceases.

4. A cam" mechanism comprising; a hub rigidly secured to a crankshaft; aprimary cam plate interposed between said hub and said crankshaft; asecondary cam plate mounted on said hub and adapted to oscillate withrespect to said primary cam plate, said secondary cam plate having anelongatedslot, said primary cam plate having a stop pin arranged totravel in said My delayed cam action arrangement can also 7 elongatedslot and restrict the travel of said secondary cam plate, spring -forresiliently holding said secondary cam plate in position against saidstop pin; a ring for holding said secondary cam plate on said ub; a'camfollower; said cam follower restricting the motion 'of said secondarycam plate; said primary cam plate having a'lobe for moving said camfollower,

whereby said secondary cam plate is released and allowed to advance,said secondary cam plate holdingsaid cam follower,in said movedpositiona predetermined length of time after the rotary movement of saidprimary cam ceases.

5. a intermittently rotating cam mechanism comprising; a hub, 'said hubbeing rigidly secured to a shaft; a primaryicam plate interposed betweensaid hub and said shaft; a secondary cam plate mounted on ,said hubadjacent said primary camplate and in axial alignment therewith,said-secondary cam plate being provided withan elongated slot, saidprimary cam plate being provided with-a stop pin adapted to travelinsaid slot and restrict the travel in said slot and restrict thetravelof said secondary cam plate with respect to said primary camplate;

a resilient means "for holding said auxiliary cam plate against saidpin; .a ring for holding said auxiliary cam plate on said hub; a camfollower; said secondary cam .plate having a lobe, said cam followerrestricting the motion of said secondary cam plate during part of therevolution .of said primary cam plate; said primary cam plate having alobe for moving said cam folplate 1 lower radially outwardly therebyreleasing said auxiliarycam plate whereby said cam follower is held insaid outward position by said auxiliary cam plate after. the primary camplate stops until the spring moves-said auxiliary cam plate toits normalposition against said stop pin.

7. An intermittently rotating cam mechanism comprising; a primary camplate, an auxiliary cam plate coupled to said primary cam'plate,

for movement therewith but with capacity for c limited independentmovement with respect" thereto, a cam follower in operative engagementwith said auxiliary cam plate, said auxiliary cam plate provided with aninstantaneous rise adapted to engage with said cam followersl wherebythe auxiliary cam plate is stopped while the primary cam plate continuesto rotate,

' said primary cam plate provided with a lobe to raisesaid cam followerto release said auxiliary cam plate; a spring means for moving saidauxiliary cam' plate with respect to said primary lower whereby saidsecondary cam plate is' released, said resilient *means causing saidsecondary cam plate to advance after, said primary cam plate stopswhereby said cam'follower'is held by saidlobe of saidauxilia'ry camplate I after the motion of saidcam plate ceases. 6. A cam mechanismcomprising; a hub rigidly secured to a shaft; a primary cam plateinterposed between said hub and said shaft; a secondary cam platemounted on said hub, said secondary cam plate being provided with anelongated slot, said primary cam ,plate being provided with'a stop pinadapted to travel'in said slot and restrict the motion of said secondarycam plate; a spring for resiliently holding said auxiliary cam plateagainst said stop pin; a means for holding said auxiliary cam plate onsaid hub; said means also adapted to vary the tension in said spring; acam follower; said primary cam plate having a lobe with a sharpriseadapted to move the cam follower radially outwardly, said secondarycam plate being provided with a substantial instantaneous rise; saidprimary cam plate and said auxiliary cam plate, said auxiliary cam'platebeing provided with an elongated lobe for engaging said cam followerafter the rotary motion of said primary cam plate ceases whereby the camfollower is held in said raised position after the rotary motion of saidprimary cam' plate ceases, said elongated lobe of said auxiliary camplate provided with a gradual drop permitting said cam follower toreturn to its lower position after the motion of said auxiliary camplate ceases.

.8. An intermittently operating cam mecha nism adapted to operate incycles of one revolution comprising; a primary cam plate, an auxiliarycam plate coupled to said primary cam plate for movement therewith butwith capacity for limited independent movement with respect thereto, acam follower in operative engagement with said primary and saidauxiliary unit, said auxiliary cam plate with respect to saidprimary camplate, said motion continuing after the rotation of said primary camplate ceases wherecam plate operating as a unit when said shaftbeginsits rotation and continuing to operate as a unit until said camfollower contacts said lobeof said secondary cam plate, said auxiliarycam plate remaining'stationary until said lobe of said primary cam platemoves the cam folby said cam follower is held in a raised position afterthe rotation of said cam plate ceases, said elongated lobe provided witha gradual drop. for permitting said cam follower to drop to its J lowerposition when said auxiliary and primary cam unit comes to rest wherebythe cam unit is automatically set for another cycle of operation.

MONTE F. WEAVER.

